From 97efe9aef1ae8922666d32f28d712745a86859e9 Mon Sep 17 00:00:00 2001 From: "holt@sgi.com" Date: Tue, 16 Aug 2011 17:32:23 +0000 Subject: [PATCH] flexcan: Prefer device tree clock frequency if available. If our CAN device's device tree node has a clock-frequency property, then use that value for the can devices clock frequency. If not, fall back to asking the platform/mach code for the clock frequency associated with the flexcan device. Signed-off-by: Robin Holt Acked-by: Wolfgang Grandegger , Cc: Kumar Gala Cc: Marc Kleine-Budde , Cc: U Bhaskar-B22300 Cc: Scott Wood Cc: Grant Likely Cc: socketcan-core@lists.berlios.de, Cc: netdev@vger.kernel.org, Cc: PPC list Cc: devicetree-discuss@lists.ozlabs.org Signed-off-by: David S. Miller --- .../bindings/net/can/fsl-flexcan.txt | 2 ++ drivers/net/can/flexcan.c | 34 ++++++++++++++----- 2 files changed, 27 insertions(+), 9 deletions(-) diff --git a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt index 8dfb98b6e3e2..1ad80d5865a9 100644 --- a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt +++ b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt @@ -11,6 +11,7 @@ Required properties: - reg : Offset and length of the register set for this device - interrupts : Interrupt tuple for this device +- clock-frequency : The oscillator frequency driving the flexcan device Example: @@ -19,4 +20,5 @@ Example: reg = <0x1c000 0x1000>; interrupts = <48 0x2>; interrupt-parent = <&mpic>; + clock-frequency = <200000000>; // filled in by bootloader }; diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index cc1e0a7b554f..e02337953f41 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #define DRV_NAME "flexcan" @@ -925,16 +926,29 @@ static int __devinit flexcan_probe(struct platform_device *pdev) struct net_device *dev; struct flexcan_priv *priv; struct resource *mem; - struct clk *clk; + struct clk *clk = NULL; void __iomem *base; resource_size_t mem_size; int err, irq; + u32 clock_freq = 0; + + if (pdev->dev.of_node) { + const u32 *clock_freq_p; - clk = clk_get(&pdev->dev, NULL); - if (IS_ERR(clk)) { - dev_err(&pdev->dev, "no clock defined\n"); - err = PTR_ERR(clk); - goto failed_clock; + clock_freq_p = of_get_property(pdev->dev.of_node, + "clock-frequency", NULL); + if (clock_freq_p) + clock_freq = *clock_freq_p; + } + + if (!clock_freq) { + clk = clk_get(&pdev->dev, NULL); + if (IS_ERR(clk)) { + dev_err(&pdev->dev, "no clock defined\n"); + err = PTR_ERR(clk); + goto failed_clock; + } + clock_freq = clk_get_rate(clk); } mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); @@ -967,7 +981,7 @@ static int __devinit flexcan_probe(struct platform_device *pdev) dev->flags |= IFF_ECHO; /* we support local echo in hardware */ priv = netdev_priv(dev); - priv->can.clock.freq = clk_get_rate(clk); + priv->can.clock.freq = clock_freq; priv->can.bittiming_const = &flexcan_bittiming_const; priv->can.do_set_mode = flexcan_set_mode; priv->can.do_get_berr_counter = flexcan_get_berr_counter; @@ -1002,7 +1016,8 @@ static int __devinit flexcan_probe(struct platform_device *pdev) failed_map: release_mem_region(mem->start, mem_size); failed_get: - clk_put(clk); + if (clk) + clk_put(clk); failed_clock: return err; } @@ -1020,7 +1035,8 @@ static int __devexit flexcan_remove(struct platform_device *pdev) mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); release_mem_region(mem->start, resource_size(mem)); - clk_put(priv->clk); + if (priv->clk) + clk_put(priv->clk); free_candev(dev); -- 2.30.2